Complete denture 1.ppt

an overview of complete denture fabrication

1. Good afternoon

2. Complete denture, Removable
partial dentures & Recent
Advances
Dr. H. Zeenath
Assistant Professor,
Dept of Prosthodontics
Govt. Dental college, TVM

3. INTRODUCTION
Complete denture is defined as “A dental prosthesis
which replaces the entire dentition and associated
structures of the maxilla and mandible”.-GPT
Partialdenture:Aprosthesisthatreplacesoneor
more,butnotallofthenaturalteethand
supportingstructures.Itissupportedbytheteeth
and/orthemucosa.Itmaybefixed(i.e.abridge)
orremovable.

4. Clinical steps
Preliminary impression
Final impression
Jaw relation
Try-in
Denture insertion
Laboratory steps
Primary or Diagnostic Cast
Special trays
Beading & Boxing
Master cast
TDB &Occlusalrims
Mounting
Arrangement of teeth
Processing & Finishing

5. Impression trays and Primary
impression

6. Animpressiontrayisdefinedas,"Adevicewhich
isusedtocarry,confineandcontrolanimpression
materialwhilemakinganimpression"-GPT.
IMPRESSION TRAYS

7. ACCORDING TO MATERIAL
•Metallic
•plastic
ACCORDING TO STRUCTURE
•Perforated
•Non-perforated
ACCORDING TO AREA OF
COVERAGE
-Quadrant -Section -Full
CLASSIFICATION OF
IMPRESSION TRAYS

8. PERFORATED & NON PERFORATED METAL AND
PLASTIC TRAYS

9. SECTIONAL
TRAYS
TRIPLE TRAY
RIM LOCK TRAYS

10. Impressions are usually poured in three pours.
Pouring the primary cast
Thecastshouldbeseparatedfromtheimpressionabout
anhouraftertheinitialset.Thepouredimpressionis
placedinawarmwaterbathtilltheimpressioncompound
softensandthecastcanbeeasilyremoved.

11. Itisatruereplicaoftheteethand
\ortheassociatedsupportingtissues.Itis
usedforfabricatingaprosthesisonit.
Cast

12. SPECIAL TRAY
Acustommadedevicepreparedforaparticular
patientwhichisusedtocarry,confineandcontrol
animpressionmaterialwhilemakingan
impression”.GPT

13. Conditioningthe primary cast
Adapting the relief wax
Adapting the spacer
Application of the separating medium and
Fabrication of a special tray
STEPS IN FABRICATION OF A
SPECIAL TRAY

14. AREASROUTINELYRELIEVEDARE……….
Incisivepapilla
Mid-palatinerapheinthemaxilla
lingualtothecrestoftheridgeinthemandible.
Additionally,reliefmayberequiredfor
Flabbyridge
Sharpmylohyoidridge
Bonyspiculesetc.
Relief

15. ADAPTING THE SPACER

16. Mostcommonlyusedmaterialsfor
makingspecialtrayare:
SHELLAC
COLDCUREACRYLIC
VACUUMFORMEDVINYLORPOLYSTYRENE
VACUUMFORMEDTHERMOPLASTIC RESIN
TYPEIIIMPRESSIONCOMPOUND (TRAYCOMPOUND)
LIGHTCURERESINS

17. SHELLAC

18. Twomajortechniquescommonlyused…
SPRINKLEONTECHNIQUE
DOUGHMETHOD
TECHNIQUE IN FABRICATION OF COLD CURE RESIN
SPECIAL TRAY

19. SPRINKLE ON TECHNIQUE
This method is commonlyused .
PROCEDURE
Make an outlineof the impression tray on the cast with
a pencil.
Block out the severe undercuts , and adapt a layer of
modelling wax to the cast as spacer.

20. Paint tinfoil substitute /seperating medium over the
stone cast and the spacer .
Sprinkle polymer powder over an area onto the cast .
Saturateit with liquid monomer with a dropper .
SPRINKLE ON TECHNIQUE

21. Apply morepowder and liquid until a uniform
thickness of 2 mm thickness is achieved.
Mix more resin and in the doughstage, form the
handle and fix it to the impression tray.
Make the handles with 3 to 4 mm of thickness,
8mm width, and 8 mm height.
SPRINKLE ON TECHNIQUE

22. After setting,remove the impression tray from the cast,
andtrim using an acrylic bur.
Examine the completed tray, and adjust and polish .
Pumice the borders of the tray lightly to make surface
smooth.
SPRINKLE ON TECHNIQUE

23. ANGULATION OF THE HANDLE
MAXILLA :12-15 degreesMANDIBLE : 90 degrees

24. DOUGH TECHNIQUE
Thepowderandliquidshouldbemixedintheratio
of3:1byvolume.
Themonomerandpolymerthemixundergoes5
differentstages:
WETSANDYSTAGE
EARLYSTRINGYSTAGE
DOUGHSTAGE
RUBBERYSTAGE
STIFFSTAGE

25. PROCEDURE
Manipulationisdoneinthelatestringyorthedough
stages.
Thematerialiskneadedwiththehand,toachievea
homogenousmix.
Thenthematerialisshapedintoa2mmthicksheet.
DOUGH TECHNIQUE

26. Flatteningthedoughcanbedoneusingarollerorby
pressingthematerialbetweenglassslabs.
Therolledsheetofacrylicisadaptedoverthecast.
DOUGH TECHNIQUE

27. TheexcessmaterialshouldbecutoutwithaB.P
blade.
Aftercutting,thematerialshouldbeheldinposition
topreventshrinkageandwarpage.
Thentrayistrimmedtoobtainasmoothsurfaceand
margins.
DOUGH TECHNIQUE

28. ROLLER TECHNIQUE

29. ADVANTAGE
This is the fastesttechnique for making special tray.
DISADVANTAGES
Expensive
A vacuum-formingmachine is required for this
procedure
VACCUM-FORMED VINYL
OR POLYSTRENE

30. .
VACcUM-FORMING CHAMBER

31. SPECIAL TRAY MADE OF LIGHT CURE RESIN

32. Afterfabricatingthespecialtray,itshouldbestoredin
thecasttillthenextappointment.
Acrylicspecialtraysshouldbestoredinwatertoavoid
warpage.
Shellactrayshouldbestoredinacooldryplace.
STORING THE SPECIAL TRAYS

33. Border molding & Final impression

34. Themastercastshouldaccuratelyreproducethe
anatomyoftheresidualridgehencecareshouldbe
takentopreservethedepthandwidthofthesulcusina
castLeave2-3mm(width)oflandarea.Thelandarea
shouldbejusthighenoughabovethedepthofthefold
sothatyoucanseethewidthofthefold.
.Thesulcuscanbepreservedbybeadingandboxing.

35. Beading and boxing
Beadingisdonetopreservethewidthandheightofthe
sulcusinacast.
Boxingisdonetoobtainuniform,smoothandwell
shapedbaseforthecast.
Specialutilitywaxesarethemostcommonlyused
materialforbeadingandboxing.Dentalplasterwith
pumicecanbeusedasanalternative.Thetechnique
forbeadingandboxingisdifferentforeachmaterial.

37. Plaster and pumice boxing
Itisindicatedforrubberbaseimpressionsas
theydonotadheretowax.Theimpressionisinvested
beforeboxing.Theinvestmentfunctionsasthe
beading.Amixtureofpumiceandplasterisusedas
theinvestingmedium.

38. Temporary record bases &
Occlusal rims

39. Itisdefinedasatemporarysubstance
representingthebaseofadenturewhichisusedfor
makingmaxillomandibularrelationrecordandfor
arrangementofteeth.
Itactsasabasalseattosupportthe
occlusalrimsandtheartificialteethforclinical
procedureslikejawrelationandtry-in.Somebase
platesarelinedwithplasticmaterialsforincreased
adaptationandstability
THE TEMPORARY DENTURE BASE

40. Auto-polymerising resins
Heat cure resins
Thermoplastic resins
Shellac
Base plate wax
Materials used for making denture base

41. Anocclusalrimisdefinedas“occludingsurfacesbuilt
ontemporaryorpermanentdenturebasesforthe
purposeofmakingmaxillomandibularrelation
recordsandarrangingteeth”-GPT.
OCCLUSAL RIMS

42. Occlusionrimsarefabricatedfor
Arrangingartificialteeth
Recordingvariousmaxillo-mandibularrelations
Markingliplines
Recordingverticalandhorizontaloverlaps,etc.
PURPOSE OF OCCLUSAL RIM

43. TECHNIQUE OF FABRICATION OF OCCLUSAL RIM
Rolled wax technique
Metal occlusal rim former
Pre-formed occlusal rim
Occlusal rims can be fabricated by using the following
techniques.

44. ROLLED WAX TECHNIQUE

45. METAL OCCLUSAL RIM FORMERS

46. PREFORMED OCCLUSAL RIMS
Theyarecommerciallyavailableinstandardsizes
separatelyforthemaxillaandmandible.

47. Itshouldbe22mmhighfromthedepthofthe
sulcusattheregionofthecanineeminence.
Theanterioredgeoftheocclusalrimatthe
midlineshouldbeabout8mmawayfromtheincisive
papilla.
MAXILLAR Y OCCLUSAL RIM

48. widthofocclusaltable
anterior:4to6mm,posterior:8to12mm
heightfromthecrestoftheridge
anterior:10-12mm,posterior:5-7mm
heightfromthedepthofsulcus(posteriorly)-18mm
MAXILLAR Y OCCLUSAL RIM

49. Itshouldbe6to8mmhighfrom
thecrestoftheridgeintheanterior
andtheposteriorregion
Itshouldbe18mmhighfromthe
depthofthesulcusinthecanine
eminenceregion.
Theocclusalplaneshouldflushto
twothirdheightoftheretromolar
padintheposteriorregion.
MANDIBULAR OCCLUSAL RIM

50. Jaw relation

51. Articulatorisdefinedasthemechanicaldevicewhich
representsthetemporomandibularjointsandjawmembers
towhichmaxillaryandmandibularcastsmaybeattached
tosimulatejawmovements.GPT
Theycanbeclassifiedas:
1.Non-adjustable[meanvaluearticulator]
2.Semi-adjustable
3.Fully-adjustablearticulators.
ORIENTATION OF OCCLUSAL RIMS
ON ARTICULATOR

52. ARTICULATORS

53. MEAN VALUE ARTICULATOR
(NON ADJUSTABLE)

54. 1 2
3
4 5
STEPS IN ARTICULATION AND MOUNTING

55. •SEMI ADJUSTABLE
HANAU ARTICULATOR (1923)
(MODEL H ) ( NON ARCON)

56. BEYRON
•SEMI ADJUSTABLE
(NON ARCON)
DENTATUS ARTICULATOR (1944)

57. Facebow transfer

60. Gothic arch tracing

61. Fully adjustable Articulator

62. ARRANGEMENT OF TEETH
INSTRUMENTS
Teeth set
Lecrons carver
Wax knife
Lead pencil
Flexible scale
Glass plate

64. Reference line drawn on cast

65. OCCLUSAL PLANE -Horizontal plane –Glass plate
SAGITAL PLANE
MID LINE
LONG AXIS OF TOOTH
VERTICAL AXIS
GUIDE LINES

66. Wax removal to place teeth
CENTRAL INCISOR

67. TO OCCLUSAL PLANECENTRAL INCISOR IN RELATION

68. INCISAL EDGE -0 .5-1mm SHORT OF
OCCLUSAL PLANE
LATERAL INCISOR

69. FRONT VEIW-LONG
AXIS PARALLEL TO
VERTICAL AXIS NECK
OF THE TOOTH IS
SLIGHTLY OUT-CANINE
PROMINENCE-DISTAL
SLOPE NOT SEEN
SIDE VEIW-LONG AXIS
PARALLEL TO
VERTICAL AXIS
OCCLUSAL PLANE -
CUSPID TIP IN CONTACT
WITH OCCLUSAL PLANE
POSITION OF CANINE

70. MAXILLARY CANINE IN THREE PLANES
FRONT–LONG AXIS PARALLEL TO VERTICAL AXIS
SIDE-LONG AXIS PARALLEL TO VERTICAL AXIS
OCCLUSAL PLANE -CUSPID TIPCONTACT
OCCLUSAL PLANE

71. ARCH FORM-use flexible scale-
canine takes a turn -corner tooth

72. FRONT VIEW-LONG
AXIS PARALLEL TO
VERTICAL AXIS
INCISAL EDGE 1-2 mm
ABOVE OCCLUSAL
PLANE
SIDE VIEW-SLOPES
LABIALLY
OCCLUSAL VIEW –
INCISAL EDGE FOLLOW
THE OUT LINE OF THE
OCCLUSAL RIM
MANDIBULAR-CENTRAL incisor

73. FRONT VIEW-LONG AXIS
PARALLEL TO VERTICAL AXIS
SIDE VIEW –LONG AXIS
SLOPES LABIALLY LESS
THAN CENTRAL INCISOR
OCCLUSAL VIEW-INCISAL
EDGE FOLLOW THE OUTLINE
OF THE OCCLUSAL RIM
MANDIBULAR –LATERAL INCISOR

74. FRONTVIEW-CUSPIDTIP OF THE CANINE
IS 0.5-1mm ABOVE THEOCCLUSAL PLANE
LONG AXIS IS TILTED MESIALLY
SIDE VIEW-SLOPES SLIGHTLY
LINGUALLY
OCCLUSAL VIEW -CUSPITIP SHOULD
FOLLOW OCCLUSAL RIM
MANDIBULAR -CANINE

75. Canine Key of Occlusion-The distal slope of lower
canine should align with mesialslope of upper canine
Improper offset results in
difficulty in arranging lower
pre molar teeth inproper
occlusion

76. OVER BITE=2mm
OVER JET=2mm
Completed
maxillary and
mandibular anterior
teeth -there should
not be any contact

77. Guide lines:
-Occlusal plane
-Lateral alignment
-Compensatory curves
-Anteroposterior
-Lateral
ARRANGEMENT OF POSTERIORS

78. CURVE OF SPEE

79. CURVE OF WILSON
LOWER POSTERIOR

80. NEUTRAL ZONE

82. WAX SCOOPED 1
ST
PREMOLAR
POSITIONED WITH
BUCCAL CUSP
CONTACTING OCCLUSAL
PLANE
1
ST
PRE MOLAR

83. 1
ST
PRE MOLAR IN RELATION TO
VERTICAL AXIS-SIDE VIEW
1
ST
PREMOLAR
PALATAL CUSP
RELATION
FIRST PREMOLAR

84. WAX SCOOPED
BOTH BUCCAL
&PALATAL CUSPS
TOUCHES THE
OCCLUSAL PLANE
2
ND
PREMOLAR

85. FRONT VIEW
SIDE VIEW-LONG
OCCLUSAL VIEW
2
ND
PRE MOLAR
IN RELATIONTO VERTICAL AXIS

86. MAXILLARY 1
ST
MOLAR

87. The buccal cusps
corresponds with the
buccal cusps of pre
molars-blue line
The palatal cusps
corresponds with the
palatal cusps of
premolars –yelow line

88. MAXILLARY-2
nd
MOLAR

89. Both the buccal cusps –
blue line palatal cusps
correspondstwith-the
1
st
molar-yellow line

90. Antero-posterior compensatory
curve

91. BUCCAL ALIGNMENT

92. Teethy
appearance
Normal dark space
behind the canine in
smile
BUCCAL CORRIDOR

93. wax scooped outReference
guideline for the
central fossa of
posterior teeth
MANDIBULAR FIRST PRE MOLAR

94. Long axis inclined
lingually when viewed
from front
Lingual cusp below the
horizontal plane buccal
cusp slightly at a higher
level

95. occlusal view
lingual view
side view long axis parallel to
vertical axis
MANDIBULAR 2
nd
-PRE MOLAR

96. Wax scooped out
Placed along the
reference line
1
st
MOLAR

97. SIDE VIEW-
mesiobuccal cusp of
maxillary 1
st
molar rests
on the buccal groove of
lower 1
st
molar
LINGUAL VIEW-
mesiopalatal cusp of
maxillary 1
st
molar inter
digitates with the
central groove of lower
1st molar

98. Occlusal view-mandibular 2
nd
molar positioned in the
reference line
Lingual view
Side view
2
nd
MOLAR

99. COMPLETED TEETH ARRANGEMENT

100. Waxing ,carving ,festooning, stippling

101. Wax added to cover cervical 1/3 of the teeth on the labial
and buccal surface
Wax melted and extended to the flange
waxing

102. Wax carved holding the
carver at 60 degree in
the anterior region
Wax carved at 20
degree
Posterior region at 45
degree

104. Semi circular sketch
for root carving vertical
line with slight distal tilt
for canine
Wax removed above the
line and in between .
FESTOONING

105. Wax removed above the
sketch
After carving

106. A brush is used
STIPPLING

107. Involves replacing the base of waxed
portions with final denture materials
Denture processing

109. Sealing: denture is sealed to the cast at
its borders with molten wax
Cast separation
It helps to maintain position of the denture.
Mainly prevents plaster from getting under the
denture.

110. Process by which trial denture is surrounded by stone /
plaster in a metal flask .
It basically creates a mould for acrylic denture.
Flasking / Investing

112. Two Pour
Three Pour
Four Pour
Ideal Material For Investing -Stone

113. Flask-Hanauflask .
Soak the cast in slurry water.
Checking the fit .
Excess height is trimmed off.
Lubricate using petroleum jelly .
Reduces the possibility of distortion
and fracture.
Deflaskingis easier.
Three Pour Technique

114. Separating media is applied at base of sides.
Stone filled in the lowest portion.
Allowed to set for 20mins.
Apply separating media over 1
st
pour .
Middle portion of flask is assembled and pour the 2
nd
mix till the occlusal surfaces of teeth and allow to set
for 20mins.
Excess stone is removed to expose cusp tips .

115. Separating Media Is Applied Again.
Stone Mix Is Poured Filling The Remainder Of Flask.
Allow To Set For 20mins.

117. First Pour
Cast Is Flasked In Lower Half.
Second Pour
Rest Of The Flask Is Filled.
 Difficult To Deflask
Risk Of Fracture
Risk Of Distortion

118. Eliminates the wax and temporary
denture base for mould space.
Place in boiling water for 5mins.
Excess time in boiling water causes
wax liquify and soak in stone.
Opened flask is flushed with
boiling water to remove remaining
wax.

119. Separating media is applied to the dewaxedmold
space prior to packing the acrylic resin
Objectives:
Prevent water from mold entering into resin which
may affect the rate of polymerisation.
Prevent monomer penetrating into mold material ,
causing plaster to adhere to the resin and producing a
rough surface.

120. Tin foil
Cellulose lacquers
Solution of alginated compounds
Calcium oleate
Soft soaps
Sodium silicate
Starches
Most commonly used separating medium is
sodium alginate solution which is also
called as ‘cold mould seal’.
Types of separating medias

121. Apply separating media on to the stone surface
excluding the teeth.
Mixed acrylic dough is formed into a roll and adapt
into mould space
A plastic separating sheet is placed over
the dough and 2 halves are closed with
pressure.

123. Polymerisation.
It is defined as forming of a compound by
joining together of molecules of small mol.Wt
into a compound of large mol.Wt.

124. Methods
Heat cure-Compression molding technique
Cold cure-
Compression molding technique
Injection molding technique
Microwave
Visible light curing system

125. Short Curing Cycle
Flask is kept in water at room temp and is
raised for 65 degree and maintain for 90 minutes
Boil for 1hr.
Equipment
Special Electrical Curing Chambers

126. Slow.
Cure at low temperature for long time for
thick dentures.
Less prone to porosity.
Temp –65-70 degree.
Time –8hrs.
No need to boil.
Long Curing Cycle

127. Less Risk Of Porosity.
Less Residual Monomer.
Indicated For Thick Acrylic
Appliances.
Advantages

128. Slow Cooling
Bench Cooling.
Fast Cooling
Bench cooling for 30mins and placing it
under running tap water for 30mins.
Cooling

129. FLUID RESIN TECHNIQUE
Pourable chemical activated resin
Resin is supplied in form of powder & liquid components
Very low viscosity resin
Completed tooth arrangement positioned in a fluid resin
flask
Preparation of sprues and vents for resin
Resin is poured into the mold cavity & allowed to polymerize
Flask is kept in pressureised chamber for 30 -45 mins
Recovery of complete denture prosthesis

130. LIGHT ACTIVATED DENTURE BASE
RESINS
Composite matrix of urethane dimethacrylate,
microfinesilica &high molecular weight acrylic resin
monomer
Activator –visible light
Initiator –camphorquinone
Supplied in sheet &rope form packed in light proof
pouches
light activated resin cannot be flaskedin conventional
manner
Opaque investing media provides the passage of light
Teeth is arranged & the denture base sculpted using
light activated resin
Denture base is placed into a light chamber
&polymerized

131. MICROWAVE CURING
Self clamping aluminium flask

132. Flasking

133. Dewaxing: The flask is placedin an 800W
(standard) microwave oven for 3 mins at
30% power (240W) .

134. Curing: The flask is placed in a 800W microwave
oven for 15 mins at 30% power (240W)

135. DEFLASKING
Removal of denture from flask using a wedge instrument.

136. Excess should be trimmed off to
reproduce the accurate details.
Abrasives
Used for polishing and finishing
irregular surfaces.
TRIMMING

137. Lathes Used For Trimming

138. Silicon carbide , boron carbide
-abrading agents.
The silicon carbide is sintered /
pressed with binder into
grinding wheels/ disks.
Eg: most of the stone burs are
made of SiC.
Carbides:

141. For trimming borders:
lathe mounted arbor band.
laboratory sized carbide burs.
For deeper frenum notches:
fissure bur mounted on lathe.
To remove stone in betn. Teeth/ to remove
acrylic nodules from denture:
pointed chisel/ fissure bur
Trimming:

142. To finish lingual border of denture:
small sized carbide bur.
To reduce thickness of palate:
large egg shaped bur.

144. FINE abrasives

145. Pumice:
Siliceous material of volcanic origin.
Used as both abrasive/polishing agent
depending on particular size.

146. A slurry of fine flour of pumice
with water is made.
The rag wheel is wetted using
the slurry and polished at low
speed.
In case of less accessible areas a
brush/ prophy cup with slurry is
used for polishing
High shine is produced using
no.341 TiGleam .
PUMICING PROCEDURES

147. Finally the denture is brushed with
green soap to remove all traces of
polishing material.
Rinse
Storage-water.

148. Recent advances in
complete dentures

149. Biofunctionalprosthetic system
BPS dentures are the product of effective
cooperation between dentists and dental
technicians.
The results are high quality tooth
replacements for discerning patients.

150. Impression Using Accu-Dent System

151. Centric Tray

152. Herbert Frick ICDE
Initial impressions with the Centric Tray study bite

154. Herbert Frick ICDE
Gnathometer Mmounted on impression trays

155. Upper and lower finished impressions

156. Perfect occlusal fit

157. Intra-oral bite registration

158. Perfect Centric

159. "Bite Registration"

160. Final Impressions with bite registration

161. Herbert Frick ICDE
Tool used to transfer jaw position to the laboratory (UTS 3D
transfer bow)

162. Stratos articulator

163. Mounting models using facebow
Herbert Frick ICDE

164. Selection of Teeth

167. Herbert Frick ICDE

168. Herbert Frick ICDE

169. Herbert Frick ICDE

170. Herbert Frick ICDE

171. Boiled-out upper and lower
injection flasks
Herbert Frick ICDE

172. Herbert Frick ICDE

173. Herbert Frick ICDE

174. Completed upper and lower dentures
Herbert Frick ICDE

175. 175

176. 176

177. 177

178. Advantages of nylon flexible denture (1955)
1. Soft and inherent flexibility:
Ability to engage undercuts for retention.
No need for periodic adjustment of clasp to
keep them tight.
Low modulus of elasticity
2. Will not warp or become brittle.
3. clinically unbreakable.
4. Good biocompatibility: because it is free of
monomer and metal.
178

179. 5. No porosity, so no bacteria can build up within it.??!!
6. No gingival inflammation
7. More comfortable
8. Absorb small amounts of water to make the denture
more soft and tissue compatible.
9. Less bulky (thinner) and lighter weight
10. Better chewing efficiency
179

180. 11. Better esthetics: Translucent, so it allows natural
gum to show through, making it invisible.
Clasps rest on the gums surrounding the natural
teeth.
They are indistinguishable from the gums.
No metal framework
12. More retention and stability
13. Retention depends mainly on the tissue and only a
small portion of abutment tooth. No evidence of
excessive abutment mobility
14. Ease of fabrication (in comparison with cast RPD)
15. Reduces chair side time (shorter fabrication time)
180

181. Disadvantages of nylon flexible denture
1.Intended only for provisional or temporary
applications.
Flexible dentures are generally only used when
traditional dentures cause discomfort to the patient
and cannot be solved through relining.
181

182. 2. A major drawback is de-bonding of the acrylic teeth
from nylon denture base. Nylon polyamide denture
base material does not bond chemically with acrylic
resin/porcelain, so mechanical undercuts (diatorics)
are made in each tooth. It cannot be used with
patients having low vertical dimension and closed
bite.
182

183. Main composition
Polyamide nylon thermoplastic material
Injection molding technique:
It is highly sensitive to the position and size of sprue
placement.
Investingin a special flask (e.gvalplastflask) and spruing.
Spruedesigning:
For complete maxillary dentures,sufficient width sprueis
attached to the posterior border of the denture with an
extension over the palate area to allow adequate flow of the
material throughout the palate area.
For partial dentures and mandibularcomplete dentures,the
sprueis attached to both lingual extensions as well as in
the midline.
183

184. Wax elimination by boiling.
Undercuts (diatorics) are made (prepared) in the
centre of each tooth so that the melted fluid
polyamide will flow into the undercuts for
mechanical retention.
After preparation, each tooth is cemented back into
its place in the top half of the flask with valcement
(cement provided with the valplast system).
N.B. Cyanoacrylate is contraindicated, because it
bonds permanently with the teeth surface.
184

185. 4. Thermoplastic nylon is melted at temperatures from
274 to 302°C for 11 min before injection.
The opened flaskis placed directly in a pre-heated
oven maintained at 65-80°C. Furnace timer was set
for 17 minutes.
The flasks halves are assembled with brackets and
together with the cartridge containing melted nylon;
they are placed on to the injection unit. The injection
molding pressure is maintained at 5 bars for 1 min.
The dental flask is bench-cooledbefore deflasking.
185

186. 186

187. 187

188. 188

189. Commercial products
Valplast
Flexiplast
Duraflex
Impak
Lucitone FRS
Flexite
Flexite M.P
Flexite Plus
Sunflex
Proflex